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extern crate proc_macro; #[macro_use] extern crate quote; #[macro_use] extern crate syn; use proc_macro::TokenStream; #[proc_macro_derive(DocumentLike, attributes(pallet))] pub fn document_derive(input: TokenStream) -> TokenStream { let input = parse_macro_input!(input as syn::DeriveInput); document_derive_inner(input).unwrap() } #[derive(Debug)] struct FieldMeta { ident: syn::Ident, name: String, ty: syn::Type, opts: proc_macro2::TokenStream, is_default_search_field: bool, } fn handle_field(input: &syn::Field) -> Result<Option<FieldMeta>, Box<dyn std::error::Error>> { let pallet_path: syn::Path = parse_quote!(pallet); let index_field_name_path: syn::Path = parse_quote!(index_field_name); let skip_indexing_path: syn::Path = parse_quote!(skip_indexing); let index_field_type_path: syn::Path = parse_quote!(index_field_type); let index_field_options_path: syn::Path = parse_quote!(index_field_options); let default_search_field_path: syn::Path = parse_quote!(default_search_field); let ident = input.ident.as_ref().unwrap(); let mut name = ident.to_string(); let mut ty = input.ty.clone(); let mut opts = quote!(std::option::Option::<()>::None); let l_attrs = input .attrs .iter() .flat_map(|x| x.parse_meta()) .filter(|x| x.path() == &pallet_path) .filter_map(|x| match x { syn::Meta::List(ml) => Some(ml), _ => None, }) .flat_map(|x| x.nested) .filter_map(|x| match x { syn::NestedMeta::Meta(m) => Some(m), _ => None, }); if l_attrs.clone().any(|x| x.path() == &skip_indexing_path) { return Ok(None); } let is_default_search_field = l_attrs.clone().any(|x| x.path() == &default_search_field_path); if let Some(index_field_name) = l_attrs .clone() .filter_map(|x| match x { syn::Meta::NameValue(mnv) => Some(mnv), _ => None, }) .filter(|x| x.path == index_field_name_path) .filter_map(|x| match x.lit { syn::Lit::Str(s) => Some(s.value()), _ => None, }) .next() { name = index_field_name; } if let Some(user_ty) = l_attrs .clone() .filter_map(|x| match x { syn::Meta::NameValue(mnv) => Some(mnv), _ => None, }) .filter(|x| x.path == index_field_type_path) .filter_map(|x| match x.lit { syn::Lit::Str(s) => syn::parse_str(&s.value()).ok(), _ => None, }) .next() { ty = user_ty; } if let Some(index_fields_options) = l_attrs .clone() .filter_map(|x| match x { syn::Meta::NameValue(mnv) => Some(mnv), _ => None, }) .filter(|x| x.path == index_field_options_path) .filter_map(|x| match x.lit { syn::Lit::Str(s) => syn::parse_str::<syn::Expr>(&s.value()).ok(), _ => None, }) .map(|e| quote!(Some(#e))) .next() { opts = index_fields_options; } Ok(Some(FieldMeta { ident: ident.clone(), name, ty, opts, is_default_search_field, })) } fn document_derive_inner( input: syn::DeriveInput, ) -> Result<TokenStream, Box<dyn std::error::Error>> { let data = match input.data { syn::Data::Struct(ref x @ syn::DataStruct { fields: syn::Fields::Named(_), .. }) => x, _ => { return Err("`Document` can only be used on a `Struct` with named fields.".into()); } }; let name = &input.ident; let pallet_path: syn::Path = parse_quote!(pallet); let tree_name_path: syn::Path = parse_quote!(tree_name); let (impl_generics, ty_generics, where_clause) = input.generics.split_for_impl(); let l_attrs = input .attrs .iter() .flat_map(|x| x.parse_meta()) .filter(|x| x.path() == &pallet_path) .filter_map(|x| match x { syn::Meta::List(ml) => Some(ml), _ => None, }) .flat_map(|x| x.nested) .filter_map(|x| match x { syn::NestedMeta::Meta(m) => Some(m), _ => None, }); let tree_name = l_attrs .clone() .filter_map(|x| match x { syn::Meta::NameValue(mnv) => Some(mnv), _ => None, }) .filter(|x| x.path == tree_name_path) .filter_map(|x| match x.lit { syn::Lit::Str(s) => Some(s.value()), _ => None, }) .next() .map(|s| quote!(Some(#s.into()))) .unwrap_or_else(|| quote!(None)); let field_metas = data .fields .iter() .map(handle_field) .filter_map(Result::transpose) .collect::<Result<Vec<_>, _>>()?; let index_fields = field_metas.iter() .map(|FieldMeta { name, ty, opts, .. }| quote!(schema_builder.add_field(<#ty as pallet::search::FieldValue>::field_entry(#name, #opts)))) .collect::<Vec<_>>(); let doc_fields = field_metas.iter().enumerate() .map(|(idx, FieldMeta { ident, ty, .. })| quote! { if let Some(val) = <#ty as pallet::search::FieldValue>::into_value(self.#ident.clone().into()) { doc.add(pallet::ext::tantivy::schema::FieldValue::new(fields[#idx], val)); } }) .collect::<Vec<_>>(); let default_search_fields = field_metas .iter() .enumerate() .filter(|(_, FieldMeta { is_default_search_field, .. })| *is_default_search_field) .map(|(idx, _)| quote!(fields[#idx])) .collect::<Vec<_>>(); let out = quote! { impl #impl_generics pallet::DocumentLike for #name #ty_generics #where_clause { type IndexFieldsType = pallet::search::FieldsContainer; fn tree_builder() -> pallet::db::TreeBuilder { let mut out = pallet::db::TreeBuilder::default(); if let std::option::Option::<std::string::String>::Some(tree_name) = #tree_name { out = out.with_tree_name(tree_name); } out } fn index_builder() -> pallet::search::IndexBuilder<Self::IndexFieldsType> { let out = pallet::search::IndexBuilder::default() .with_fields_builder(|schema_builder| { Ok(pallet::search::FieldsContainer(vec![#(#index_fields,)*])) }) .with_default_search_fields_builder(|fields| { let fields = &fields.0; vec![#(#default_search_fields,)*] }); out } fn as_index_document( &self, index_fields: &Self::IndexFieldsType, ) -> pallet::err::Result<pallet::ext::tantivy::Document> { use pallet::search::FieldValue; let fields = &index_fields.0; let mut doc = pallet::ext::tantivy::Document::new(); #(#doc_fields)* Ok(doc) } } }; Ok(out.into()) }